Update x4: 1st 2nd3rd 4th Screenshot shown (its early but progressing, first Libretro Core Running on PS4)
At some point we know we will eventually see a port of RetroArch on the PS4, just look at all the devices the multi-emulation project already supports with its Libretro Cores and RetroArch frontend . However, could we be getting closer to seeing not only a great PS4 Homebrew hit the console but a port of RetroArch to natively hit the PS4? With recent advancements in the scene such as OpenGL ES (via flatz) it now seems that the early steps have begun as developerfrangarcjhas started to push some commits in relations to a PS4 port as seen here on the developer's Github account. Looks like we are early in the journey and development has just begun and likely will take sometime for a proper release (so be patient), but nonetheless its great to see the progress being made by the developer who made similar possibilities on the PS Vita / PSTV. Also in a slightly unrelated note, there has been alot of progress on the PS2 port of RetroArch being developed as well (checkout latest details from the developer).

@frangarcj is a very valued team member, since he pretty much did the PS Vita port as well along with some help from xerpi. Anyway, great to see this! Between this and the PS2 port, RetroArch will soon have a port on all PlayStation platforms (except for PS1 OFC).

Obviously what you see is not ideal yet, height is split in half right now, but what you see there is RetroArch running on a PlayStation4! It's using the OpenGL video driver and running XMB. It's early days but the promise of this port is that we will be able to leverage OpenGL!-Libretro

10x UPDATE (January 20) - Now the 10th Video Released >>> The next PS3 NVidia RSX accelerated X.org steps(Original Article from Nov. 14) Is the PS3 a bit closer to gaining Hardware Acceleration (via RSX) in OtherOS (Linux) with a proper driver to enable the GPU chip? We are not there, but we may be getting closer to a reality. Earlier this year (back in April) we detailed some of the progress that the busy dev RenéRebe has made with unlocking the potential of the PlayStation 3's RSX chip and now today we have been greeted with a new video and what we can expect with this project as the developer starts to undertake the challenge of further unlocking one more component of the Ps3 hardware,. The developer has alot of videos on other intresting subjects in his diverse YouTube channel >>> (Bits and More) <<< many very informative video's..​

Following the big news from Team Molecule several weeks ago and effectively opening the system wide open, it was only a matter of time before we would start to see other developer's start putting the finding to use and we have seen the FAPS Team (team members listed below)have recently released a new (taiHEN) plugin called ref00d, this plugin is a big deal, as it will allows users/devs to use content that would otherwise require a higher firmware to be played/executed on a lower firmware for your exploited PS Vita or PlayStation TV. Typically not an easy task to reach but thanks to Team Molecule's research and the FAPS Team we now have a ready to use simple plugin solution to remove those firmware restrictions, see additional details about this plugin release in the release notes provided below by the development team.
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Update (2x): Reports are coming in this PS2 Homebrew is also working on PS3 HAN & PS4 (5.05). With progress making headway on the upcoming PS4 port of RetroArch from a group of developer's, Another developer (fjtrujy) started progress on a PlayStation 2 (PS2) port several months back (view previous progress) and now has a port that progressed enough for a public soft release, Now available in the new RetroArch PS2 Nighties for anyone interested in downloading and trying out the multi-system emulator on your homebrew capable PS2 hardware. @fjtrujy warns that many things need implemented yet and many pending issue remain and only these early release contains two cores currently 2048 and QuickNES. Which is likely to grow and a good gauge to base what is expected for the PS2 port, Would be to view the PSP as that should be a good baseline of what to expect and the PS2 may be able to handy more then the PSP likely.​

I have retroarch on my tablet, PC, and the Wii.
To have this on the PS4 someday will be a dream for me. (Better controller!)

Keep up the good work.
I agree with @antonioks and believe it's important to keep spreading these emulators into the next generations. That is my opinion is the best way to preserve a way we can play games we all enjoy.